Fingerprint sensing method, fingerprint sensor, and display device including the same

ABSTRACT

A fingerprint sensor includes a substrate, a light blocking layer that is on a first surface of the substrate and includes openings in a light blocking mask, and a sensor layer that is on a second surface of the substrate and includes photo sensors. A fingerprint sensing method of the fingerprint sensor includes: storing a calibration image; generating an original image, based on sensing signals from the photo sensors; performing calibration on the original image by utilizing the calibration image; and detecting a fingerprint, based on the calibrated image. The calibration image is generated by synthetizing valid regions extracted from an original calibration image corresponding to the original image.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/943,534, filed Jul. 30, 2020, which claims priority to and thebenefit of Korean Patent Application No. 10-2019-0105124, filed Aug. 27,2019, the entire content of both of which is incorporated herein byreference.

BACKGROUND 1. Field

One or more aspects of embodiments of the present disclosure generallyrelate to a fingerprint sensing method, a fingerprint sensor, and adisplay device including the same.

2. Related Art

A photosensitive type fingerprint sensor may include a light source andphoto sensors. Each photo sensor may receive reflected light generatedby a fingerprint of a user, and a fingerprint detector may detect thefingerprint by generating and processing an original image, based on thereflected lights.

The reflected light received by the photo sensor may include noise, orthe original image may include noise (or error) due to a deviation ofthe photo sensor (and a light path). In order to remove the noise fromthe original image, the fingerprint detector may perform whitecalibration (or calibration) on the original image. For example, thefingerprint detector may calibrate the original image by using a whitecalibration image (or calibration data) that is pre-generated/pre-storedbased on ambient light received by the photo sensor.

An optical structure may be disposed on an optical path between thefingerprint of the user and the photo sensor, and reflected lightgenerated by the fingerprint may be provided to only some of photosensors in a sensing region according to a disposition position of theoptical structure (e.g., a distance from the optical structure to thefingerprint and a distance from the optical structure to the photosensor). That is, a substantially valid region (i.e., a valid region)for fingerprint detection may be limited to only a portion in theoriginal image. Nevertheless, the white calibration image may be storedwith respect to the whole of the sensing region which may increasestorage space and loading time of the white calibration data.

SUMMARY

Aspects of some example embodiments are directed to a fingerprintsensing method, a fingerprint sensor, and a display device including thesame, which can minimize or reduce a storage space of a whitecalibration image and decrease a loading time of the white calibrationimage.

Aspects of some example embodiments are directed to a fingerprintsensing method, a fingerprint sensor, and a display device including thesame, which can decrease a time for which white calibration is performedon an original image acquired through photo sensors (i.e., a timerequired to perform the white calibration).

One or more example embodiments of the present disclosure provide afingerprint sensor including: a substrate; a light blocking layer on afirst surface of the substrate, the light blocking layer includingopenings in a light blocking mask; a sensor layer on a second surface ofthe substrate, the sensor layer including photo sensors; and afingerprint detector configured to generate an original image, based onsensing signals from the photo sensors, to perform calibration on theoriginal image by using a calibration image, and to detect afingerprint, based on the calibrated image, wherein the calibrationimage is generated by synthesizing valid regions extracted from anoriginal calibration image corresponding to the original image.

The light blocking layer may transfer some a first light incident intothe light blocking layer to the sensor layer through the openings, andblock a second light.

A first one of the photo sensors may be to receive light through oneopening, and a second one of the photo sensors may be to receive nolight or to receive lights through two or more openings.

The valid regions may be generated based on sensing signals from firstphoto sensors from among the photo sensors configured to receive lightthrough one opening.

The original calibration image may be generated based on sensing signalsoutput from the photo sensors in response to light of a skin color.

The calibration image may be generated by extracting the valid regionsin the original calibration image and putting together the validregions.

The calibration image may have a capacity smaller than that of theoriginal calibration image.

The fingerprint detector may extract the valid regions in the originalimage, generate a synthetic image by putting together the extractedvalid regions, and perform calibration on the synthetic image by usingthe calibration image.

The fingerprint detector may perform the calibration by loading thecalibration image and subtracting the calibration image from thesynthetic image.

The fingerprint detector may perform at least one image-processing amongsmoothing, binarization, and thinning on the valid regions or thesynthetic image.

The fingerprint sensor may further include: a circuit element layer onthe light blocking layer, the circuit element layer having at least oneconductive layer constituting circuit elements; and a light emittingelement layer on the circuit element layer, the light emitting elementlayer including light emitting elements.

One or more example embodiments of the present disclosure provide afingerprint sensing method of a fingerprint sensor including asubstrate, a light blocking layer that is on a first surface of thesubstrate and includes openings in a light blocking mask, and a sensorlayer that is on a second surface of the substrate and includes photosensors, the fingerprint sensing method including: storing a calibrationimage; generating an original image, based on sensing signals from thephoto sensors; performing calibration on the original image by using thecalibration image; and detecting a fingerprint, based on the calibratedimage, wherein the calibration image is generated by synthetizing validregions extracted from an original calibration image corresponding tothe original image.

The valid regions may be regions generated based on sensing signals fromfirst photo sensors from among the photo sensors configured to receivelight through one opening.

The original calibration image may be generated based on sensing signalsoutput from the photo sensors in response to light of a skin color.

The calibration image may be generated by extracting the valid regionsin the original calibration image and putting together the validregions.

The performing of the calibration may include: extracting the validregions in the original image; generating a synthetic image by puttingtogether the extracted valid regions; loading the calibration image; andsubtracting the calibration image from the synthetic image.

The fingerprint sensing method may further include, before the loadingof the calibration image, performing at least one image-processing amongsmoothing, binarization, and thinning on the valid regions or thesynthetic image.

One or more example embodiments of the present disclosure provide adisplay device including: a substrate; a light blocking layer on a firstsurface of the substrate, the light blocking layer including openings ina light blocking mask; a circuit element layer on the light blockinglayer, the circuit element layer having at least one conductive layer inwhich circuit elements are disposed; a light emitting element layer onthe circuit element layer, the light emitting element layer includinglight emitting elements; a sensor layer on a second surface of thesubstrate, the sensor layer including photo sensors; and a fingerprintdetector configured to generate an original image, based on sensingsignals from the photo sensors, perform calibration on the originalimage by using a calibration image, and detect a fingerprint, based onthe calibrated image, wherein the calibration image is generated bysynthesizing valid regions extracted from an original calibration imagecorresponding to the original image.

The valid regions may be regions generated based on sensing signals fromfirst photo sensors from among the photo sensors configured to receivelight through one opening.

The original calibration image may be generated based on sensing signalsoutput from the photo sensors in response to light of a skin color.

BRIEF DESCRIPTION OF THE DRAWINGS

Example embodiments will now be described more fully hereinafter withreference to the accompanying drawings; however, they may be embodied indifferent forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will convey thescope of the example embodiments to those skilled in the art.

In the drawing figures, dimensions may be exaggerated for clarity ofillustration. It will be understood that when an element is referred toas being “between” two elements, it can be the only element between thetwo elements, or one or more intervening elements may also be present.Like reference numerals refer to like elements throughout.

FIGS. 1 and 2 are schematic plan views illustrating a display deviceaccording to some embodiments of the present disclosure.

FIGS. 3A-3E are plan views illustrating an arrangement structure ofpixels and photo sensors according to some embodiments of the presentdisclosure.

FIG. 4 is a schematic cross-sectional view of a display panel accordingto some embodiments of the present disclosure.

FIG. 5 is a plan view illustrating a light blocking layer according tosome embodiments of the present disclosure.

FIG. 6 is a schematic cross-sectional view of a display panel accordingto some embodiments of the present disclosure.

FIG. 7 is a schematic cross-sectional view of a display panel accordingto some embodiments of the present disclosure.

FIG. 8 is a schematic cross-sectional view of a display panel accordingto some embodiments of the present disclosure.

FIG. 9 is a block diagram illustrating a configuration of a fingerprintdetector according to some embodiments of the present disclosure.

FIGS. 10-12 are views illustrating a method of generating a whitecalibration image according to some embodiments of the presentdisclosure.

FIGS. 13-17 are views illustrating a processing method of an originalimage according to some embodiments of the present disclosure.

FIG. 18 is a flowchart illustrating a fingerprint sensing method of afingerprint sensor according to some embodiments of the presentdisclosure.

DETAILED DESCRIPTION

Hereinafter, exemplary embodiments of the present disclosure will bedescribed in more detail with reference to the accompanying drawings.Throughout the drawings, the same reference numerals are given to thesame elements, and their overlapping descriptions may be omitted.

FIGS. 1 and 2 are plan views schematically illustrating a display devicein accordance with some embodiments of the present disclosure. Forexample, FIGS. 1 and 2 are views schematically illustrating a displaypanel 110 provided in the display device 10 in accordance with someembodiments of the present disclosure and a driving circuit 200 fordriving the display panel 110. Although the display panel 110 and thedriving circuit 200 are separated from each other in FIGS. 1 and 2, thepresent disclosure is not limited thereto. For example, the whole or aportion of the driving circuit may be integrally implemented with thedisplay panel 110 (e.g., on the display panel 110 as a monolithicstructure).

Referring to FIGS. 1 and 2, the display device 10 includes a displaypanel 110 and a driving circuit 200 for driving the display panel 110.

The display panel 110 includes a display region AA and a non-displayregion NA. The display region AA, which may be referred to as an activeregion, is a region in which a plurality of pixels PXL, which may bereferred to as sub-pixels, are provided. In some embodiments, each ofthe pixels PXL may include at least one light emitting element. Thedisplay device 10 drives the pixels PXL, corresponding to image datainput from the outside, thereby displaying an image in the displayregion AA.

In some embodiments of the present disclosure, the display region AA mayinclude a sensing region SA. The sensing region SA may include at leastsome pixels from among the pixels PXL provided in the display region AA.

In some embodiments, as shown in FIG. 1, at least a portion of thedisplay region AA may be set as the sensing region SA. In someembodiments, as shown in FIG. 2, the whole of the display region AA maybe set as the sensing region SA.

Although only one sensing region SA is formed on (or in) the displayregion AA in FIG. 1, embodiments of the present disclosure are notlimited thereto. For example, in some embodiments, a plurality ofsensing regions SA that are regularly or irregularly arranged may beformed on (or in) the display region AA. In some embodiments, theplurality of sensing regions SA may have areas and shapes, which areidentical to or different from each other.

Although the sensing region SA is formed in at least a portion of thedisplay region AA in FIG. 1, embodiments of the present disclosure arenot limited thereto. For example, in some embodiments, the displayregion AA and the sensing region SA may be provided to overlap with eachother in at least a partial region.

The non-display region NA is a region disposed at the periphery of thedisplay region AA, and may be referred to as a non-active region. Insome embodiments, the non-display region NA may inclusively mean theother region except the display region AA on the display panel 110. Insome embodiments, the non-display region NA may include a line region, apad region, various dummy regions, and the like.

In some embodiments of the present disclosure, the display device 10 mayfurther include a plurality of photo sensors PHS provided in the sensingregion SA. In some embodiments, each of the photo sensors PHS may sensereflected light generated when light emitted from a light source (e.g.,a pixel PXL) is reflected by a finger of a user, and the display device10 may sense a fingerprint of the finger of the user by analyzing thereflected lights. Hereinafter, although an example in which the photosensors PHS are used for fingerprint sensing is described, the photosensors PHS may be used to perform various functions of a touch sensor,a scanner, or the like.

In some embodiments of the present disclosure, the photo sensors PHS maybe arranged or provided in the sensing region SA. The photo sensors PHSmay overlap with at least some or all of the pixels PXL provided in thesensing region SA, or be arranged at the periphery of the pixels PXL.For example, at least some or all of the photo sensors PHS may beprovided between the pixels PXL. Some embodiments of an arrangementrelationship between the photo sensors PHS and the pixels PXL will bedescribed in more detail with reference to FIGS. 3A-3E.

In some embodiments, the photo sensors PHS are provided adjacent to thepixels PXL, the photo sensors PHS may use, as a light source, a lightemitting element provided in at least one pixel PXL disposed in thesensing region SA or at the periphery thereof. Therefore, the photosensors PHS along with the pixels PXL of the sensing region SA,particularly, the light emitting elements provided in the pixels PXL mayconstitute a photosensitive type fingerprint sensor. As described above,when a display device having a built-in fingerprint sensor is configuredusing the pixels PXL as light sources, without any external lightsource, the module thickness of the photosensitive type fingerprintsensor and the display device having the same can be decreased, andmanufacturing cost can be reduced.

In some embodiments, the photo sensors PHS may be arranged or providedon the other surface (e.g., a rear surface) opposing (e.g., facing awayfrom) a surface (e.g., a front surface) on which an image is displayedamong both surfaces of the display panel 110. However, embodiments ofthe present disclosure are not limited thereto.

The driving circuit 200 may drive the display panel 110. For example,the driving circuit 200 may output a data signal corresponding to imagedata to the display panel 110 or output a driving signal for the photosensor PHS, and receive a sensing signal received from the photo sensorPHS. The driving circuit 200 receiving the sensing signal may detect afingerprint (or fingerprint shape) of a user by using the sensingsignal.

In some embodiments of the present disclosure, the driving circuit 200may include a panel driver 210 and a fingerprint detector 220. Althoughthe panel driver 210 and the fingerprint detector 220 are separated fromeach other in FIGS. 1 and 2, embodiments of the present disclosure isnot limited thereto. For example, at least a portion of the fingerprintdetector 220 may be integrated with the panel driver 210 or operate inconnection with the panel driver 210.

The panel driver 210 may supply a data signal corresponding to imagedata to the pixels PXL while sequentially scanning the pixels PXL of thedisplay region AA. Then, the display panel 110 may display an imagecorresponding to the image data.

In some embodiments, the panel driver 210 may supply a driving signal(e.g., a first driving signal) for fingerprint sensing to the pixelsPXL. The driving signal may be provided to allow the pixels PXL tooperate as light sources for the photo sensors PHS by emitting lights.Therefore, the driving signal for fingerprint sensing may be provided topixels PXL provided in a specific region of the display panel 110, e.g.,pixels PXL provided in the sensing region SA. In some embodiments, thedriving signal for fingerprint sensing may be provided by thefingerprint detector 220.

The fingerprint detector 220 may provide or transfer a driving signal(e.g., a second driving signal) for driving the photo sensors PHS to thephoto sensor PHS, and detect a fingerprint of a user, based on sensingsignals received from the photo sensors PHS. A detailed fingerprintdetection method of the fingerprint detector 220 will be described indetail below with reference to FIGS. 9-17.

FIGS. 3A-3E are plan views illustrating some embodiments of anarrangement structure of pixels and photo sensors. FIGS. 3A-3Eillustrate different embodiments of relative sizes, resolutions, andarrangement relationships between at least one pixel PXL and photosensors PHS, which are provided in the sensing region SA.

Referring to FIG. 3A, photo sensors PHS may be arranged with aresolution (density) equal to or substantially equal to that of pixelsPXL in the sensing region SA. In other words, the photo sensors PHS ofwhich number is equal to or substantially equal to that of the pixelsPXL may be arranged in the sensing region SA. In some embodiments, thepixels PXL and the photo sensors PHS may be arranged to form pairs,respectively. In some embodiments as shown in FIG. 3A, a case where thepixels PXL and the photo sensors PHS are arranged to overlap with eachother is illustrated. However, in some embodiments, the pixels PXL andthe photo sensors PHS may be arranged not to overlap with each other orto overlap with each other only in one region.

Although the photo sensors PHS have a size smaller than that of thepixels PXL in FIG. 3A, embodiments of the present disclosure are notlimited thereto. For example, each of the photo sensors may be largerthan each of the pixels PXL as illustrated in FIG. 3C. In someembodiments, the photo sensors PHS may have a size equal to,substantially equal to, or larger than that of the pixels PXL.

Referring to FIGS. 3B-3E, photo sensors PHS may be arranged with aresolution lower than that of pixels PXL in the sensing region SA. Inother words, a smaller (or lesser) number of the photo sensors PHS thanthe number of the pixels PXL may be arranged in the sensing region SA.Although one photo sensor PHS is disposed per four pixels PXL in FIGS.3B-3E, embodiments of the present disclosure are not limited thereto.

In some embodiments, the photo sensors PHS may have a size smaller thana size of the pixels PXL as shown in FIGS. 3B and 3E, or have a sizelarger than a size of the pixels PXL as shown in FIGS. 3C and 3D.

When the photo sensors PHS are arranged with a resolution lower than aresolution of the pixels PXL, some or all of the photo sensors PHS maybe arranged to overlap with pixels PXL. For example, the photo sensorsPHS may partially overlap with some of the pixels PXL as shown in FIGS.3B and 3C.

In some embodiments, the photo sensors PHS may be disposed between thepixels PXL as shown in FIG. 3D to partially overlap with the pixels PXL.For example, one or more portions of each of the photo sensors PHS mayoverlap with one or more pixels PXL and one or more other portions ofeach of the photo sensors PHS may not overlap with one or more pixelsPXL when viewed in a plan view as shown in FIG. 3D. In some embodiments,the photo sensors PHS (e.g., each of the photo sensors PHS) may have asize larger than that of the pixels PXL (e.g., each of the pixels PXL)as shown in FIG. 3D. For example, the photo sensors PHS (e.g., each ofthe photo sensors PHS) may have a size large enough to cover at leastone pixel PXL.

In some embodiments, the photo sensors PHS may not overlap with thepixels PXL as shown in FIG. 3E. In some embodiments, no portion of thephoto sensors PHS overlaps with the pixels PXL when viewed in a planview as shown in FIG. 3E.

In some embodiments of the present disclosure, the arrangement structurebetween the pixels PXL and the photo sensors PHS is not limited to thosedescribed above. That is, the shapes, arrangements, relative sizes,numbers, and resolutions of the pixels PXL and of the photo sensors PHSin the sensing region SA may be variously modified in a suitable mannerwithout departing from the technical concept of the present disclosure.Also, in some embodiments of the present disclosure, the pixels PXL andthe photo sensors PHS may be arranged in a form obtained by combiningone or more of the embodiments shown in FIGS. 3A-3E.

Although the photo sensors PHS are regularly arranged (e.g., arranged ina definite pattern) in the sensing region SA in FIGS. 3A-3E, embodimentsof the present disclosure are not limited thereto. In some embodiments,the photo sensors PHS may be irregularly arranged in the sensing regionSA.

FIG. 4 is a schematic cross-sectional view of a display panel inaccordance with some embodiments of the present disclosure. Inparticular, FIG. 4 illustrates a cross-sectional view of the displaydevice 10 shown in FIGS. 1 and 2 in the sensing region SA.

Referring to FIG. 4, the sensing region SA of the display device 10 inaccordance with some embodiments of the present disclosure may includethe display panel 110 and a sensor layer PSL disposed on one surface ofthe display panel 110. Also, the display device 10 may include asubstrate SUB, and a circuit element layer BPL, a light emitting elementlayer LDL, a first protective layer PTL1, a first adhesive layer ADL1,and a window WIN, which are sequentially disposed on one surface (e.g.,an upper surface) of the substrate SUB. Also, the display device 10 mayinclude a second adhesive layer ADL2 and a second protective layer PTL2,which are sequentially disposed on another surface (e.g., a lowersurface) of the substrate SUB.

The substrate SUB is a base substrate of the display panel 110, and maybe a transparent or substantially a transparent transmissive substrate.The substrate SUB may be a rigid substrate including glass or temperedglass, or a flexible substrate made of plastic. However, the material ofthe substrate SUB is not limited thereto, and the substrate SUB may bemade of various suitable materials.

The substrate SUB may include a display region AA and a non-displayregion NA as shown in FIGS. 1 and 2. In some embodiments, the displayregion AA may include a plurality of pixel regions PXA in which therespective pixels PXL are disposed and/or formed.

The circuit element layer BPL may be disposed on the one surface of thesubstrate SUB, and include at least one conductive layer. For example,the circuit element layer BPL may include a plurality of circuitelements (e.g., at least one transistor and at least one capacitor)constituting pixel circuits of the pixels PXL and lines for supplyingvarious power sources and signals for driving the pixels PXL. Thecircuit element layer BPL may include circuit elements and a pluralityof conductive layers for constituting lines connected to the circuitelements. Also, the circuit element layer BPL may include at least oneinsulating layer provided between the plurality of conductive layers.Also, the circuit element layer BPL may include a line part disposed inthe non-display region NA of the substrate SUB to supply correspondingpower sources and corresponding signals to lines connected to the pixelsPXL.

The light emitting element layer LDL may be disposed on one surface ofthe circuit element layer BPL. The light emitting element layer LDL mayinclude a plurality of light emitting elements LD connected to thecircuit elements and/or the lines of the circuit element layer BPLthrough contact holes, etc. In some embodiments, at least one of theplurality of light emitting elements LD may be disposed in each of thepixel regions PXA as shown in FIG. 4.

Each of the pixels PXL may include circuit elements disposed in thecircuit element layer BPL and at least one light emitting element LDdisposed in the light emitting element layer LDL on the top of thecircuit element layer BPL. A structure of the pixel PXL may be describedin detail later.

The first protective layer PTL1 may be disposed on the top of the lightemitting element layer LDL to cover the display region AA. The firstprotective layer PTL1 may include an encapsulating member such as a thinfilm encapsulation (TFE) or an encapsulation substrate, and additionallyinclude a protective film, and the like in addition to the encapsulatingmember.

The first adhesive layer ADL1 is disposed between the first protectivelayer PTL1 and the window WIN to couple the first protective layer PTL1and the window WIN to each other. The first adhesive layer ADL1 mayinclude a transparent adhesive such as an optically clear adhesive(OCA), and include various adhesive materials in addition to thetransparent adhesive.

The window WIN is a protective member disposed at a module uppermostportion of the display device 10 including the display panel 110, andmay be substantially a transparent transmissive substrate. The windowWIN may have a multi-layered structure selected from a glass substrate,a plastic film, and a plastic substrate. The window WIN may include arigid or flexible substrate, and the material constituting the windowWIN is not particularly limited.

In some embodiments of the present disclosure, the display device 10 mayfurther include a polarizing plate and/or a touch sensor layer (touchelectrode layer). For example, the display device 10 may further includea polarizing plate and/or a touch sensor layer, disposed between thefirst protective layer PTL1 and the window WIN.

The second protective layer PTL2 may be disposed on the other surface ofthe substrate SUB. The second protective layer PTL2 may be coupled tothe substrate SUB by the second adhesive layer ADL2.

The second adhesive layer ADL2 may firmly couple (or attach) thesubstrate SUB and the second protective layer PTL2 to each other. Thesecond adhesive layer ADL2 may include a transparent adhesive such as anOCA. The second adhesive layer ADL2 may include a pressure sensitiveadhesive (PSA) in which an adhesive material acts when pressure forallowing the second adhesive layer ADL2 to be adhered to an adhesivesurface is applied. When the second adhesive layer ADL2 includes thePSA, the second adhesive layer ADL2 may be attached to the adhesivesurface by using pressure without separate thermal treatment or UVtreatment at room temperature.

In some embodiments of the present disclosure, the second adhesive layerADL2 may include a material absorbing specific light or include amaterial blocking the specific light. In an example, the second adhesivelayer ADL2 may include an infrared absorbing material absorbing infraredlight having a high energy density or include an infrared blockingmaterial blocking the infrared light.

The infrared absorbing material may include, for example, an inorganicbased oxide such as Antimony Tin Oxide (ATO), Indium Tin Oxide (ITO),tungsten oxide, or carbon black, and/or a metal such as Ag. Theinorganic based oxide may selectively transmit light of a visible regionand absorb infrared light. Also, the infrared absorbing material mayinclude, for example, an organic based dye. The organic base dye may bea dye used as a color filter provided in the display panel 110.

The infrared blocking material may be, for example, at least oneselected from a borate mixture, a carbonate mixture, an alumina mixture,a nitrate mixture, a nitrite mixture, lithium borate, potassium borate,magnesium borate, calcium borate, strontium borate, barium borate,sodium borate, Na₂B₄O_(x), colemanite, lithium carbonate, sodiumcarbonate, potassium carbonate, calcium carbonate, calcite, CaCO₃,dolomite, and/or magnesite. Also, the infrared blocking material may beat least one selected from one or more dyes selected from nickel dithiolbased, dithiol based metal complex compounds, cyanine based, squaryliumbased, croconium based, diimmonium based, aminium based, ammonium based,phthalocyanine based, naphthalocyanine based, anthraquinone based,naphthoquinone based, polymer condensation azo-based pyrrole,polymethine-based, and/or propylene-based.

When a hand (or finger) of a user is mounted (or located) on a displaysurface (e.g., one surface on which an image is displayed) of thedisplay device 10, the display device 10 may perform a function ofsensing a fingerprint of the user through photo sensors PHS which may bedescribed later. When external light introduced to the display device 10while the display device 10 is sensing the fingerprint of the user, avisible region in the external light is blocked by the hand of the user,but infrared light may be transmitted through the hand of the user andthen incident into (e.g., on) the photo sensors PHS. The infrared lightincident into (e.g., on) the photo sensors PHS serves as noise, andtherefore, the recognition accuracy of light reflected by the hand ofthe user may be decreased.

In the above-described embodiment of the present disclosure, when thesecond adhesive layer DAL2 includes the infrared absorbing materialand/or the infrared blocking material, the infrared light is absorbedand/or blocked by the second adhesive layer ADL2 even though theinfrared light of the external light is transmitted through the hand ofthe user. Hence, the infrared light is not incident into (e.g., on) thephoto sensors PHS, and thus the recognition accuracy of the fingerprintof the user can be improved.

The second protective layer PTL2 prevents or substantially preventsoxygen and moisture from being introduced thereto from the outside, andmay be provided in the form of a single layer or multi-layer. The secondprotective layer PTL2 may be configured in a film form, to furtherensure flexibility of the display panel 110. The second protective layerPTL2 may be coupled to the sensor layer PSL through another adhesivelayer including a transparent adhesive such as an OCA.

In some embodiments, a selective light blocking film may be furtherprovided on the bottom of the second protective layer PTL2. Theselective light blocking film blocks a specific frequency region (e.g.,ultraviolet light in external light introduced to the display device 10)to prevent or substantially prevent the corresponding light from beingincident into (e.g., on) photo sensors PHS. Although the selective lightblocking film is described as provided on the bottom of the secondprotective layer PTL2, embodiments of the present disclosure are notlimited thereto. For example, in some embodiments, the selective lightblocking film may be provided in any layer of the display device 10 aslong as the selective light blocking film is disposed on the top of thesensor layer PSL. In some embodiments, when a component for blocking theultraviolet light is included in the display panel 110, the selectivelight blocking film may be omitted.

A light blocking layer PHL may be disposed between the light emittingelement layer LDL and the sensor layer PSL which may be described later.For example, the light blocking layer PHL may be disposed between thesubstrate SUB and the circuit element layer BPL as shown in FIG. 4. Insome embodiments of the present disclosure, the light blocking layer PHLmay include a plurality of pin holes PIH. The light blocking layer PHLblocks lights incident from the outside (e.g., some of reflected lightsreflected from a finger), and therefore, only the others of thereflected lights reaches a lower layer through the pin holes PIH.

A width (or diameter) of the pin holes PIH may be configured such thatlight satisfying an observation view of a set (e.g., predetermined)angle range (or referred to as “field of view (FOV) θ”) can betransmitted through each pin hole PIH.

Also, the width (or diameter) of the pin holes PIH may be set to aboutten times of the wavelength of reflected light (e.g., about 4 μm orabout 5 μm) such that diffraction of light can be prevented or reduced.Also, the width of the pin holes PIH may be set large enough to preventor reduce image blur and to more clearly sense the shape of afingerprint. For example, the width of the pin holes PIH may be set toabout 20 μm or less. However, the present disclosure is not limitedthereto, and the width of the pin holes PIH may vary depending on awavelength band of reflected light and/or a module thickness for eachlayer.

A distance (or pitch) between adjacent pin holes PIH may be set byconsidering a distance between the light blocking layer PHL and thesensor layer PSL and a wavelength range of reflected light. For example,the distance between the adjacent pin holes PIH may be set to twice ormore of that between the light blocking layer PHL and the sensor layerPSL which may be described later. The distance between the adjacent pinholes PIH may be set to no less than a value obtained by adding a set(e.g., predetermined) error range to the distance between the lightblocking layer PHL and the sensor layer PSL. Thus, images observed bythe respective photo sensors PHS can be prevented or substantiallyprevented from overlapping with each other, and accordingly, the imageblur can be prevented or reduced.

The sensor layer PSL may be attached to the other surface (e.g., therear surface) of the display panel 110 to overlap with at least oneregion of the display panel 110. The sensor layer PSL may be disposed tooverlap with the display panel 110 in the display region AA. The sensorlayer PSL may include a plurality of photo sensors PHS distributed at aset (e.g., predetermined) resolution and/or a set (e.g., predetermined)distance. A distance between the photo sensors PHS may be densely setsuch that reflected light reflected from an observation object (e.g., aspecific region of a finger, such as a fingerprint region) can beincident into at least two adjacent photo sensors PHS.

The photo sensors PHS of the sensor layer PSL may receive reflectedlights passing through the pin holes PIH, and output electrical signalscorresponding to the reflected lights as sensing signals. Reflectedlights incident into the respective photo sensors PHS may have differentoptical characteristics (e.g., frequencies, wavelengths, sizes, etc.),based on whether the reflected lights are caused by valleys or ridges ofa fingerprint formed on a finger of a user. Therefore, the photo sensorsPHS may output sensing signals having different electricalcharacteristics, corresponding to the optical characteristics of thereflected lights. The sensing signals output by the photo sensors PHSmay be converted into an original image, in some embodiments, sensorimage, sensor data, and/or sensor image data may be used for fingerprintidentification of the user.

As described above, the display device 10 in accordance with the presentdisclosure has a fingerprint sensor including the light emitting elementlayer LDL, the sensor layer PSL, and the light blocking layer PHL. Thelight emitting element layer LDL may include the light emitting elementsLD capable of serving as a light source of a photosensitive typefingerprint sensor. The sensor layer PSL may include the photo sensorsPHS for receiving reflected light that is emitted from the lightemitting element layer LDL and then reflected from an object (e.g., afingerprint region of the finger) located on the top of the displaydevice 10. The light blocking layer PHL may include the pin holes PIHdisposed between the light emitting element layer LDL and the sensorlayer PSL to allow reflected lights to be selectively transmittedtherethrough.

In some embodiments, the fingerprint sensor may further include anoptical opening region formed in the display panel 110, etc. (e.g.,formed in the circuit element layer BPL and the light emitting elementlayer LDL) so as to reduce loss of reflected light incident into eachpin hole PIH within a set (e.g., predetermined) range of FOV. Also, inorder to more easily control the FOV, the fingerprint sensor may includea light control layer disposed in the display panel 110 to control alight path. Some embodiments of the light control layer will bedescribed below with reference to FIGS. 6-8.

In some embodiments, the display device 10 uses the light emittingelements LD of the pixels PXL as the light source of the fingerprintsensor, but the present disclosure is not limited thereto. For example,a display device in accordance with some embodiments of the presentdisclosure may have a separate light source for fingerprint sensing.

The fingerprint sensing method of the display device 10 in accordancewith the above-described embodiment may be briefly described as follows.During a fingerprint sensing period in which the photo sensors PHS areactivated, the pixels PXL (particularly, the light emitting elements LDprovided in the pixels PXL) of the display region AA may emit lights ina state in which a finger (e.g., a fingerprint region) of a user is incontact with or comes close to the display region AA. For example, allthe pixels PXL of the display region AA may simultaneously (e.g.,concurrently) or sequentially emit lights during the fingerprint sensingperiod. In some embodiments, only some pixels PXL among the pixels PXLof the display region AA emit lights at a set (e.g., predetermined)distance, or only some pixels PXL radiating lights of a specific color(e.g., short-wavelength light such as blue light) may selectively emitlights.

Some of lights emitted from the pixels PXL may be reflected from thefinger of the user and then incident into the photo sensors PHS bypassing through the optical opening region formed in each layer of thedisplay device 10 and the pin holes PIH. A fingerprint shape(fingerprint pattern) of the user may be detected based on differencesin light amount and/or waveforms of reflected lights respectivelyreflected from ridges and valleys of the fingerprint.

In some embodiments, as shown in FIG. 4, only at least some of the photosensors PHS disposed in the sensor layer PSL may receive incident lightaccording to a size (e.g., width) of the pin holes PIH and/or a FOV θ.In some embodiments, only sensing signals output by photo sensors thatactually receive reflected lights among sensing signals output by thephoto sensors PHS may be used as valid sensing signals for fingerprintdetection. Sensing signals output by photo sensors PHS that do notreceive reflected lights blocked by the pin holes PIH may includeinvalid information corresponding to only black.

In some embodiments, one or more of the photo sensors PHS disposed inthe sensor layer PSL may receive reflected light from one pin hole PIH,and other ones of the photo sensors PHS may receive reflected lightsfrom at least two pin holes PIH. In some embodiments, only sensingsignals output by photo sensors PHS that receive reflected light fromone pin hole PIH may be used as valid sensing signals for fingerprintdetection. Sensing signals output by photo sensors PHS that receivereflected lights from a plurality of pin holes PIH may includeinaccurate information due to mutual interference between the receivedreflected lights.

Therefore, the fingerprint detector 220 shown in FIGS. 1 and 2 mayextract a valid region generated based on valid sensing signals in anoriginal image generated from sensing signals, and detect a fingerprint,based on the extracted valid region. For example, the fingerprintdetector 220 may extract valid regions in the original image generatedbased on the sensing signals, and synthesize the extracted valid regionsby performing image-processing on the valid regions. Each of the validregions may be defined as a region, partial image, or a portion ofsensor data generated based on sensing signals of photo sensors PHS thatreceive reflected light through one pin hole PIH in the original image(or sensor data) generated from the sensing signals output by the photosensors PHS.

A fingerprint detection method of the fingerprint detector 220 may bedescribed in more detail below with reference to FIGS. 9-17.

FIG. 5 is a plan view illustrating a light blocking layer in accordancewith some embodiments of the present disclosure.

Referring to FIG. 5, the light blocking layer PHL in accordance withsome embodiments of the present disclosure may include a light blockingmask LBM and a plurality of pin holes PIH distributed in the lightblocking mask LBM.

The light blocking mask LBM may be made of a light blocking materialand/or a light absorbing material. For example, the light blocking maskLBM may be configured with an opaque metal layer (conductive layer)locally opened in a region in which each pin hole PIH is disposed.However, the material constituting the light blocking mask LBM is notlimited to metal, and the light blocking mask LBM may be made of variousmaterials capable of blocking transmission of light. For example, thelight blocking mask LBM may be made of a black matrix material currentlyknown in the art or any other suitable material.

The pin holes PIH may be openings distributed in the light blocking maskLBM. The pin holes PIH may be distributed in a uniform, substantiallyuniform, or irregular pattern in the light blocking mask LBM to have acertain size and distance. Also, the pin holes PIH may be arranged witha resolution lower than a resolution of the photo sensors PHS arrangedin the sensor layer PSL. However, the present disclosure is not limitedthereto, and the size, number, resolution, and/or arrangement structureof the pin holes PIH may be variously modified in a suitable manner.

Although the pin holes PIH have a rectangular shape in FIG. 5,embodiments of the present disclosure are not limited thereto. Forexample, in some embodiments, the pin holes PIH may have various shapessuch as a rectangular shape, a circular shape, an elliptical shape, anda polygonal shape.

In the display device 10 shown in FIG. 4, the light blocking layer PHLmay be disposed between the light emitting element layer LDL in whichthe light emitting elements LD are arranged and the sensor layer PSL inwhich the photo sensors PHS are arranged. The light blocking layer PHLmay constitute an optical system for allowing only some lights to beselectively transmitted therethrough and blocking the other light.

The light blocking layer PHL along with the photo sensors PHS describedabove may constitute a finger print sensor. Also, the light blockinglayer PHL may be integrally formed with the circuit element layer of thedisplay panel 110. Thus, the module thickness of the photosensitive typefingerprint sensor and the display device having the same can bedecreased or be minimized or reduced.

FIG. 6 is a schematic cross-sectional view of a display panel inaccordance with some embodiments of the present disclosure. FIG. 7 is aschematic cross-sectional view of a display panel in accordance withsome embodiments of the present disclosure. FIG. 8 is a schematiccross-sectional view of a display panel in accordance with someembodiments of the present disclosure. In FIGS. 6-8, detaileddescriptions of components similar or identical to those at least one ofthe above-described embodiments may be omitted.

Referring to FIG. 6, the circuit element layer BPL may include a lighttransmitting hole array layer LTHL provided or disposed in the sensingregion SA. For example, the light transmitting hole array layer LTHL mayinclude a plurality of light transmitting holes LTH distributed in thecircuit element layer BPL. In some embodiments, the light transmittinghole array layer LTHL may be provided in substitution for the lightblocking layer PHL. That is, the light transmitting holes LTH mayrespectively serve as the pin holes PIH.

When the pin holes PIH are configured using the plurality of lighttransmitting holes LTH distributed in the circuit element layer BPL,without separately providing the light blocking layer PHL as shown inFIG. 6, a separate mask process to form the light blocking layer PHL maybe omitted. In addition, the display device in accordance with someembodiment shown in FIG. 6 can prevent or reduce an increase inthickness, which is caused when the light blocking layer PHL isseparately provided. Further, manufacturing cost can be reduced, andprocess efficiency can be improved.

Referring to FIGS. 7 and 8, the circuit element layer BPL may include alight transmitting hole array layer LTHL including a plurality of lighttransmitting hole LTH. In some embodiments, a light blocking layer PHLincluding a plurality of pin holes PIH may be disposed between thesubstrate SUB and the circuit element layer BPL. The light transmittingholes LTH and the pin holes PIH may be arranged such that at least someof the light transmitting holes LTH and the pin holes PIH overlap witheach other.

In some embodiments of the present disclosure, the light transmittingholes LTH and the pin holes PIH may have sizes equal to, substantiallyequal to, or different from each other. For example, the lighttransmitting holes LTH may have a width (or diameter) smaller than thatof the pin holes PIH as shown in FIG. 7. For example, the lighttransmitting holes LTH and the pin holes PIH have a width (or diameter)ranging from 5 μm to 20 μm, and the width (or diameter) of the lighttransmitting holes LTH may be smaller than that of the pin holes PIH.

In some embodiments, the light transmitting holes LTH have a sizesmaller than that of the pin holes PIH. Therefore, the lighttransmitting hole array layer LTHL may serve as a light control layerLBL for controlling the path of light (e.g., limiting the FOV ofreflected light to a set (e.g., predetermined) angle range), and thelight blocking layer PHL may perform a light blocking function.

In contrast to FIG. 7, in some embodiments, the light transmitting holesLTH may have a width (or diameter) greater than that of the pin hole PIHas shown in FIG. 8. In some embodiments, the light transmitting holearray layer LTHL may perform a light blocking function, and the lightblocking layer PHL may serve as the light control layer LBL forcontrolling the path of light.

FIG. 9 is a block diagram illustrating a configuration of a fingerprintdetector in accordance with some embodiments of the present disclosure.FIGS. 10-12 are views illustrating a method of generating a whitecalibration image in accordance with some embodiments of the presentdisclosure. FIGS. 13-17 are views illustrating a processing method of anoriginal image in accordance with some embodiments of the presentdisclosure.

Referring to FIG. 9, the fingerprint detector 220 in accordance withsome embodiments of the present disclosure may include a whitecalibration image storage 221 (or calibration data storage), an imageprocessor 222, and a white calibrator 223 (or calibrator). Although thecomponents are independent from each other in FIG. 9, embodiments of thepresent disclosure are not limited thereto. In some embodiments, atleast some of the white calibration image storage 221, the imageprocessor 222, and the white calibrator 223 may be integrated as onecomponent or be separated into more than one component. In someembodiments, the white calibration image storage 221 may be a storagedevice separately provided at the outside (e.g., the panel driver 210shown in FIGS. 1 and 2, etc.) of the fingerprint detector 220.

The white calibration image storage 221 may store a white calibrationimage (or calibration data) used for white calibration. The whitecalibration may be defined as a calibration operation of removing anoise, error, or deviation generated in an original image due to aprocess deviation of the photo sensor PHS (see FIG. 4), the pin hole PIH(see FIG. 4), the optical opening region, etc., thereby ensuringuniformity of the photo sensors PHS in the sensor layer PSL (see FIG.4). The white calibration image may be stored in the white calibrationimage storage 221 before the display device 10 having the fingerprintdetector 220 is initially driven (e.g., before a product is released).

In some embodiments, the white calibration image may be generated usingthe following method. First, an original white calibration image (i.e.,calibration data about all the photo sensors PHS) as shown in FIG. 10may be generated based on sensing signals output from the photo sensorsPHS by sensing light of a color (e.g., a skin color) of an object to bedetected on the display panel 110. A sensing signal received from onephoto sensor PHS may be converted to constitute one pixel in theoriginal white calibration image (or to constitute a value correspondingto the one pixel).

In some embodiments, the original white calibration image may begenerated by converting sensing signals output from the photo sensorsPHS into image data in a state in which an object having a skin color oran object having a specific reflectivity (e.g., a reflectivity of about70%) is disposed on the display panel 110. In some embodiments, theoriginal white calibration image may be generated by converting sensingsignals output from the photo sensors PHS into image data in a state inwhich light of a skin color is irradiated onto the display panel 110.The original white calibration image may include a noise or error (e.g.,a noise with respect to a color of an object to be detected) caused by aprocess deviation of the photo sensor PHS (see FIG. 4), etc.

As described with reference to FIG. 4, only some photo sensors PHS thatsubstantially receive reflected lights or receive reflected light fromone pin hole PIH among the photo sensors PHS may output valid sensingsignals. In some embodiments, the original white calibration image maybe processed such that a valid region EA generated based on the validsensing signals remains.

Specifically, valid regions EA may be extracted from the original whitecalibration image as shown in FIG. 11. Only some of the valid regions EAextracted from the original white calibration image shown in FIG. 10 areexemplarily illustrated in FIG. 11. The valid region EA may mean aregion, partial image, or a portion of sensor data generated based onsensing signals of photo sensors PHS that receive reflected lightthrough one pin hole PIH in the original white calibration image.

The extracted valid regions EA may be synthesized, to generate a finalwhite calibration image. For example, the extracted valid regions EA maybe put together (or stitched together), to be combined as one image asshown in FIG. 12.

In some embodiments, when the valid regions EA are synthesized, imageinterpolation may be applied to pixels included in edge regions that areput together. For example, the image interpolation may be performed bycalculating a mean value of image data of a corresponding pixel and anadjacent pixel. In some embodiments, the image interpolation may beperformed using an original white calibration image of an invalid regioninstead of the valid image EA. The image interpolation may be performedin various methods known in the art, and is not limited to a specificmethod.

Because the final white calibration image generated in accordance withsome embodiments of the present disclosure as shown in FIG. 12 isgenerated using only the extracted valid regions EA, the final whitecalibration image has a capacity smaller than that of the original whitecalibration image shown in FIG. 10. Thus, the fingerprint sensor inaccordance with the present disclosure can decrease a storage spacerequired to store the white calibration image. Further, because thefinal white calibration image generated in accordance with the presentdisclosure has a small capacity, a loading time of the white calibrationimage can be decreased when white calibration is performed using thefinal white calibration image.

The image processor 222 may generate an original image (or sensor data),based on sensing signals received from the outside (e.g., the photosensors PHS) and perform image-processing on the original image. Asdescribed with reference to FIG. 4, during the fingerprint sensingperiod, the pixels PXL of the display region AA (or sensing region SA)emit lights, some of the lights are reflected from a finger of a user,and the reflected lights are incident into the photo sensors PHS throughthe pin holes PIH. Sensing signals from photo sensors PHS receiving thereflected lights may be provided to the image processor 222.

Specifically, the image processor 222 may convert the sensing signalsreceived from the photo sensors PHS into an original image as shown inFIG. 13. A sensing signal received from one photo sensor PHS may beconverted to constitute one pixel in the original image.

In some embodiments, the image processor 222 may receive coordinateinformation from the outside (e.g., the panel driver 210 shown in FIG.1, etc.) The coordinate information may include information on aposition at which contact of an object to be sensed (e.g., touch of afinger occurs in the sensing region SA shown in FIG. 1). When thecoordinate information is received, the image processor 222 may extracta touch region TA corresponding to a corresponding coordinate in anoriginal image as shown in FIG. 14, and perform an operation which maybe described on only the extracted touch region TA.

In some embodiments, when the sensing region is limited to a specificregion on the display panel 110 as shown in FIG. 1, the image processor222 may not separately receive coordinate information. Therefore, theimage processor 222 may perform the operation which may be describedlater on the whole of the original image.

In the following embodiments, a case where the image processor 222receives coordinate information and performs image-processing on onlythe touch region TA is described. However, the following embodiments maybe identically applied even when the image processor 222 performsimage-processing on the whole of the original image without receivingthe coordinate information.

The image processor 222 may extract valid regions EA from an originalimage (i.e., an original image corresponding to the touch region TA) asshown in FIG. 15. Only some of the valid regions EA extracted from theoriginal image shown in FIG. 14 are exemplarily illustrated in FIG. 15.The valid region EA may mean a region generated based on a sensingsignal of a photo sensor that receives reflected light through one pinhole PIH.

In some embodiments, the image processor 222 may performimage-processing on the extracted valid regions EA.

For example, the image processor 222 may perform smoothing on the validregions EA as shown in FIG. 16. For example, the image processor 222 mayincrease brightness separation with respect to the valid regions EA, andremove noise, etc. The smoothing may be performed through histogramanalysis with respect to each of pixels in an original image. Forexample, the smoothing may be performed using a median filter method.The smoothing may be performed using various suitable algorithms knownin the art, and the method of performing the smoothing is notparticularly limited.

In some embodiments, the image processor 222 may perform binarizationand thinning on the extracted valid regions EA. For example, the imageprocessor 222 may convert a plurality of grayscale levels or gray levels(e.g., at least corresponding one among 256 grayscale levels or graylevels) of the valid regions EA into a value corresponding to 0 (black)or 1 (white). Then, ridges constituting a fingerprint may be clearlydefined as black, and valleys constituting the fingerprint may beclearly defined as white. Also, the image processor 222 may generate aline image in which the width of the ridges is one pixel from abinarized image. The binarization and thinning are performed to improvethe accuracy of fingerprint detection, and may be omitted when thebinarization and thinning are not required.

In some embodiments, when at least one of the above-describedimage-processing operations are omitted or are desired, a larger numberof image-processing operations may be performed. For example, when theoriginal image is a sufficiently satisfactory image having a smallamount of noise, the smoothing may not be performed.

The image processor 222 may generate one image by synthesizing the validregions EA image-processed as described above. For example, the imageprocessor 222 may generate one synthetic image, synthetic data, orsynthetic image data as shown in FIG. 17 by putting together theextracted valid images EA.

The white calibrator 223 may perform white calibration on the syntheticimage generated by the image processor 222. Specifically, the whitecalibrator 223 may load white calibration image from the whitecalibration image storage 221. The white calibrator 223 may performwhite calibration on the synthetic image, based on the white calibrationimage. For example, the white calibrator 223 may differentiate (orsubtract) the white calibration image from the synthetic image. Becausethe white calibration image includes noise as described above, the noisemay be removed from the synthetic image through image differentiation.

In some embodiments of the present disclosure, the white calibrationimage has a form, size, or capacity reduced (or compressed) as comparedwith the original white calibration image as described above. Therefore,the white calibration in accordance with the present disclosure may beapplied to a synthetic image after image synthesis is performed by theimage processor.

A final image (i.e., calibrated sensor data) calibrated by the whitecalibrator 223 may be used to detect a fingerprint. For example, in thecase of fingerprint registration, the fingerprint detector 220 may storea final image and information related to the final image in thefingerprint detector 220 or in a separate storage space provided at theoutside. The stored final image may be used as reference data whenfingerprint detection is performed subsequently.

In the case of fingerprint authentication, the fingerprint detector 220may acquire a final image from the outside or determine whether thefingerprint authentication has succeeded by comparing the final imagewith the reference data stored in the fingerprint detector 220.

FIG. 18 is a flowchart illustrating a fingerprint sensing method of thefingerprint sensor in accordance with some embodiments of the presentdisclosure. In particular, FIG. 18 is a flowchart illustrating afingerprint sensing method of the fingerprint detector shown in FIG. 1.

Referring to FIGS. 9-18, the fingerprint detector 220 may store a whitecalibration image (or calibration image) (1801). The white calibrationimage may be generated by extracting valid regions (or partial datahaving a valid value) from an original white calibration image (i.e.,calibration data about all photo sensors) and synthesizing the extractedvalid regions.

A method of generating a white calibration image is the same asdescribed with reference to FIGS. 9-12, and therefore, its detaileddescription may be omitted.

In some embodiments of the present disclosure, generation and storage ofa white calibration image may be performed at least once before thedisplay device 10 is initially driven (e.g., before a product isreleased). However, embodiments of the present disclosure are notlimited thereto, and the generation and storage of the white calibrationimage may be performed after the display device 10 is initially driven.

In some embodiments, the white calibration image may be generated byanother external device to be transferred to the fingerprint detector220. Therefore, a step of receiving the white calibration image from theoutside may be performed before the step of storing the whitecalibration image.

The fingerprint detector 220 may receive sensing signals from the photosensors PHS (1802). The fingerprint detector 220 may receive sensingsignals from the photo sensors PHS when contact of an object to besensed occurs according to a set (e.g., predetermined) period or on thedisplay panel 110. However, the present disclosure is not limitedthereto.

In some embodiments, the fingerprint detector 220 may receive coordinateinformation from the panel driver 210, etc. The coordinate informationmay include information on a position at which contact of an object tobe sensed (e.g., touch of a finger) occurs. When the coordinateinformation is received, the fingerprint detector 220 may perform anoperation, which may be described later, on sensing signals receivedfrom photo sensors PHS at a position corresponding to the coordinateinformation among the sensing signals received from the photo sensorsPHS.

The fingerprint detector 220 may generate an original image (or sensordata) from the received sensing signals (1803). For example, thefingerprint detector 220 may generate an original image by convertingone sensing signal received from one photo sensor PHS into one pixelimage.

The fingerprint detector 220 may extract valid regions from thegenerated original image (1804). The valid region may be a regiongenerated based on a sensing signal of a photo sensor receivingreflected light through one pin hole.

The fingerprint detector 220 may perform image-processing on theextracted valid regions (1805). The image-processing may include, forexample, at least one of smoothing, binarization, and thinning. However,embodiments of the present disclosure are not limited thereto, and alarger or smaller number of image processing techniques may be appliedaccording to embodiments of the present disclosure. Also, in someembodiments, the step of performing image-processing may be omitted.

The fingerprint detector 220 may synthesize the image-processed validregions (1806). For example, the fingerprint detector 220 may generateone synthetic image (or synthetic data) by putting together theimage-processed valid regions. In some embodiments, the synthesis of thevalid regions may be performed before the valid regions areimage-processed.

The fingerprint detector 220 may perform white calibration on thesynthetic image (1807). Specifically, the fingerprint detector 220 mayload a pre-stored white calibration image. The fingerprint detector 220may remove noise from the synthetic image by differentiating the loadedwhite calibration image from the synthetic image.

The fingerprint detector 220 may detect a fingerprint, based on a finalimage on which the white calibration is performed (1808). Thefingerprint detector 220 may store information on the extractedfingerprint, or further perform a required operation such asauthentication by comparing the information on the extracted fingerprintwith information on a pre-stored fingerprint.

In the fingerprint sensing method, the fingerprint sensor, and thedisplay device including the same in accordance with the presentdisclosure, only valid regions (i.e., calibration values correspondingto photo sensors that validly operate) are extracted and synthesized inan original white calibration image (i.e., calibration image of allphoto sensors), and the synthesized image is stored as a final whitecalibration image. Thus, a storage space of the white calibration imagecan be minimized or reduced, and a loading time of the white calibrationimage can be decreased.

Also, in the fingerprint sensing method, the fingerprint sensor, and thedisplay device including the same in accordance with the presentdisclosure, valid regions are extracted and synthesized from an originalimage (i.e., sensed data) acquired through photo sensors, and whitecalibration is performed on the synthetic image, so that the timerequired to perform white calibration on the original image acquiredthrough the photo sensors can be decreased.

It will be understood that, although the terms “first”, “second”,“third”, etc., may be used herein to describe various elements,components, regions, layers and/or sections, these elements, components,regions, layers and/or sections should not be limited by these terms.These terms are only used to distinguish one element, component, region,layer or section from another element, component, region, layer orsection. Thus, a first element, component, region, layer or sectiondiscussed below could be termed a second element, component, region,layer or section, without departing from the spirit and scope of theinventive concept.

As used herein, “a plan view”,”may refer to a view from top or from adirection normal to the display area (or display plane) of the displaydevice.

Spatially relative terms, such as “beneath”, “below”, “lower”, “under”,“above”, “upper”, “rear” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. It will beunderstood that the spatially relative terms are intended to encompassdifferent orientations of the device in use or in operation, in additionto the orientation depicted in the figures. For example, if the devicein the figures is turned over, elements described as “below” or“beneath” or “under” other elements or features would then be oriented“above” the other elements or features. Thus, the example terms “below”and “under” can encompass both an orientation of above and below. Thedevice may be otherwise oriented (e.g., rotated 90 degrees or at otherorientations) and the spatially relative descriptors used herein shouldbe interpreted accordingly. In addition, it will also be understood thatwhen a layer is referred to as being “between” two layers, it can be theonly layer between the two layers, or one or more intervening layers mayalso be present.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the inventiveconcept. As used herein, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises” and/or “comprising,” when used in this specification,specify the presence of stated features, integers, steps, operations,elements, and/or components, but do not preclude the presence oraddition of one or more other features, integers, steps, operations,elements, components, and/or groups thereof. As used herein, the term“and/or” includes any and all combinations of one or more of theassociated listed items. Expressions such as “at least one of,” whenpreceding a list of elements, modify the entire list of elements and donot modify the individual elements of the list. Further, the use of“may” when describing embodiments of the inventive concept refers to“one or more embodiments of the inventive concept.” Also, the term“exemplary” is intended to refer to an example or illustration.

It will be understood that when an element or layer is referred to asbeing “on”, “connected to”, “coupled to”, or “adjacent to” anotherelement or layer, it can be directly on, connected to, coupled to, oradjacent to the other element or layer, or one or more interveningelements or layers may be present. In contrast, when an element or layeris referred to as being “directly on,” “directly connected to”,“directly coupled to”, or “immediately adjacent to” another element orlayer, there are no intervening elements or layers present.

Example embodiments have been disclosed herein, and although specificterms are employed, they are used and are to be interpreted in a genericand descriptive sense only and not for purpose of limitation. In someinstances, as would be apparent to one of ordinary skill in the art asof the filing of the present application, features, characteristics,and/or elements described in connection with a particular embodiment maybe used singly or in combination with features, characteristics, and/orelements described in connection with other embodiments unless otherwisespecifically indicated. Accordingly, it will be understood by those ofskill in the art that various changes in form and details may be madewithout departing from the spirit and scope of the present disclosure asset forth in the following claims, and equivalents thereof.

What is claimed is:
 1. A fingerprint sensor comprising: photo sensors; alight blocking layer on the photo sensors, the light blocking layercomprising a light blocking mask having openings; and a fingerprintdetector configured to generate an original image, based on sensingsignals from the photo sensors, to perform calibration on the originalimage by utilizing a calibration image, and to detect a fingerprint,based on the calibrated image, wherein the calibration image isgenerated by synthesizing valid regions extracted from an originalcalibration image corresponding to the original image.
 2. Thefingerprint sensor of claim 1, wherein the light blocking layer isconfigured to transfer a first light incident into the light blockinglayer to the photo sensors through the openings, and block a secondlight.
 3. The fingerprint sensor of claim 1, wherein a first one of thephoto sensors is configured to receive light through one opening, and asecond one of the photo sensors is configured to receive no light or toreceive light through two or more openings.
 4. The fingerprint sensor ofclaim 1, wherein the valid regions are generated based on sensingsignals from first photo sensors from among the photo sensors configuredto receive light through one opening.
 5. The fingerprint sensor of claim4, wherein the original calibration image is generated based on sensingsignals output from the photo sensors in response to light of a skincolor.
 6. The fingerprint sensor of claim 5, wherein the calibrationimage is generated by extracting the valid regions in the originalcalibration image and putting together the valid regions.
 7. Thefingerprint sensor of claim 6, wherein the calibration image has acapacity smaller than that of the original calibration image.
 8. Thefingerprint sensor of claim 6, wherein the fingerprint detector isconfigured to extract the valid regions in the original image, togenerate a synthetic image by putting together the valid regions, and toperform calibration on the synthetic image by utilizing the calibrationimage.
 9. The fingerprint sensor of claim 8, wherein the fingerprintdetector is further configured to perform the calibration by loading thecalibration image and subtracting the calibration image from thesynthetic image.
 10. The fingerprint sensor of claim 8, wherein thefingerprint detector is further configured to perform at least oneimage-processing among smoothing, binarization, and thinning on thevalid regions or the synthetic image.
 11. The fingerprint sensor ofclaim 1, further comprising: a circuit element layer on the lightblocking layer, the circuit element layer having at least one conductivelayer constituting circuit elements; and a light emitting element layeron the circuit element layer, the light emitting element layercomprising light emitting elements.
 12. A fingerprint sensing method ofa fingerprint sensor comprising photo sensors, and a light blockinglayer on the photo sensors, the light blocking layer comprising a lightblocking mask having openings, the fingerprint sensing methodcomprising: storing a calibration image; generating an original image,based on sensing signals from the photo sensors; performing calibrationon the original image by utilizing the calibration image; and detectinga fingerprint, based on the calibrated image, wherein the calibrationimage is generated by synthetizing valid regions extracted from anoriginal calibration image corresponding to the original image.
 13. Thefingerprint sensing method of claim 12, wherein the valid regions aregenerated based on sensing signals from first photo sensors from amongthe photo sensors configured to receive light through one opening. 14.The fingerprint sensing method of claim 13, wherein the originalcalibration image is generated based on sensing signals output from thephoto sensors in response to light of a skin color.
 15. The fingerprintsensing method of claim 14, wherein the calibration image is generatedby extracting the valid regions in the original calibration image andputting together the valid regions.
 16. The fingerprint sensing methodof claim 15, wherein the performing of the calibration comprises:extracting the valid regions in the original image; generating asynthetic image by putting together the valid regions; loading thecalibration image; and subtracting the calibration image from thesynthetic image.
 17. The fingerprint sensing method of claim 16, furthercomprising, before the loading of the calibration image, performing atleast one image-processing among smoothing, binarization, and thinningon the valid regions or the synthetic image.
 18. A display devicecomprising: photo sensors; a light blocking layer on the photo sensors,the light blocking layer comprising a light blocking mask havingopenings; a circuit element layer on the light blocking layer, thecircuit element layer having at least one conductive layer in whichcircuit elements are disposed; a light emitting element layer on thecircuit element layer, the light emitting element layer comprising lightemitting elements; and a fingerprint detector configured to generate anoriginal image, based on sensing signals from the photo sensors, toperform calibration on the original image by utilizing a calibrationimage, and to detect a fingerprint, based on the calibrated image,wherein the calibration image is generated by synthesizing valid regionsextracted from an original calibration image corresponding to theoriginal image.
 19. The display device of claim 18, wherein the validregions are generated based on sensing signals from first photo sensorsfrom among the photo sensors configured to receive light through oneopening.
 20. The display device of claim 19, wherein the originalcalibration image is generated based on sensing signals output from thephoto sensors in response to light of a skin color.